Akademik Veri Yönetim Sistemi
Tezin Türü: Doktora
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Kimya Bölümü, Türkiye
Tezin Onay Tarihi: 2018
Tezin Dili: İngilizce
Öğrenci: Derya Özhava
Danışman: SAİM ÖZKAR
Özet:Ammonia borane (AB) has been considered as a chemical hydrogen storage materials, because of its high hydrogen storage capacity (19.6 wt%), nontoxicity, and stability under ordinary conditions. Hydrogen stored in AB can be liberated by thermolysis or solvolysis. Hydrolysis and methanolysis are the two solvolysis reactions producing hydrogen gas from AB. Although the hydrolysis of AB has been investigated for years extensively, the methanolysis of AB has been considered as an alternative way of releasing hydrogen gas due to many advantages over hydrolysis. As for the hydrolysis, the hydrogen liberation from the methanolysis of AB also realized in the presence of a suitable catalyst. This dissertation covers the preparation and characterization of rhodium(0) nanoparticles supported on the surface of nanooxide materials (Rh(0)/nanooxides), namely hydroxyapatite, silica, alumina and ceria, as well as the examination of their catalytic activities in hydrogen generation from the methanolysis of AB. Firstly, Rh(0)/nanooxides were prepared in a simple and reproducible way by impregnating rhodium(III) or (II) ions on the surface of nanooxide followed by their reduction during the methanolysis of AB. They were then isolated from the reaction medium and characterized by using a combination of advance analytical techniques including ATR-IR, PXRD, TEM, HR-TEM, TEM – EDX, STEM-EDS, XPS, SEM, SEM-EDX, ICP-OES and N2 adsorption/desorption. Then, the kinetics of methanolysis of AB in the presence of Rh(0)/nanooxides were examined depending on catalyst concentration and temperature as well as catalytic lifetime, and heterogeneity tests were performed. Furthermore, the formation kinetics vi of rhodium(0) nanoparticles supported on nanosilica, nanoalumina or nanoceria during hydrogen generation from methanolysis of AB were investigated by using the hydrogen generation as reporter reaction.